This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present invention that are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In a transmission of digitally compressed video, a very important source of impairments comes from the delivery of the video stream over an error-prone channel. Partial loss or partial corruption of information can have a dramatic impact on user's perceived quality because a localized distortion within a frame can spatially and temporally propagate over frames. The visual impact of such frame loss varies between video decoders depending on their ability to deal with corrupted streams. In some cases, a decoder may decide to drop some frames on its own initiative. For example, a decoder can entirely drop or discard the frame that has corrupted or missing information and repeat the previous video frame instead until the next valid decoded frame is available. Encoders can also drop frames during a sudden increase of motion in the content in a case that the target encoding bit rate is too low. In all the-above case, we call a frame loss occurs in a video.
In many existing video quality monitoring products, the overall video quality of a media will be analyzed based on three main coding artifacts, which are jerkiness, blockiness and blurring. Blockiness and blurring are two main kinds of spatial coding artifacts which behave as discontinuity in block boundary and high frequency loss respectively. While jerkniess is the most important temporal artifacts.
A temporal video quality degradation caused by a set of group frame losses is called a jerkiness, wherein the group frame loss means a fact that one or more consecutive frames in a video sequence are lost together.
There are some studies about the evaluation of the perceptual impact of (periodic and non-periodic) video frame losses on perceived video quality.
In K. C. Yang, C. C. Guest, K. EI-Maleh and P. K. Das, “Perceptual Temporal Quality Metric for Compressed Video”. IEEE Transaction on Multimedia, vol.9, no.7, November 2007, pp.1528-1535 (hereinafter referred to as prior art 1), it was pointed out that humans usually have higher tolerance to consistent frame loss and the negative impact is highly related to the consistency of frame loss, which is then be used as a measurement of jerkiness.
In R. R. Pastrana-Vidal and J. C. Gicquel, “Automatic Quality Assessment of Video Fluidity Impairments Using a No-Reference Metric”, the 2nd International Workshop on Video Processing and Quality Metric for Consumer Electronics, Scottsdale, USA 22-24, January 2006 (hereinafter referred to as prior art 2), the relationship between perceptual impacts of jerkiness and the length and occurrence frequency of the group frame losses was mentioned.